This invention relates to an apparatus and method of extracting oil from oil-bearing plant parts, and more particularly, to an apparatus and method of extracting plant oil using a hydrocarbon solvent agent.
Plant oils have been extracted from plant material for centuries. Many plant oils are extracted from seeds by squeezing or crushing the seeds to force out the oil therefrom. Mechanical oil extractors or expellers are extensively used for obtaining cold-pressed oils where the temperature of starting material does not exceed 120° F. In order to increase the oil output, the oil extraction methods provide for the addition of heat and pressure.
In addition, plant oils can be extracted with the assistance of a chemical agent or solvent, such as hexane. Chemical extraction is cheaper and more efficient than mechanical extraction, at a large scale, leaving only 0.5-0.7% of the oil in the plant solids, as compared to 6-14% for mechanical extraction.
Plant seeds and pods are not the only plant components that contain oil. Fibrous plant matter, including leaves, flowers, etc. contain significant amounts of plant oil that can be extracted and used in cosmetics, healthcare industries and the like. Many solutions have been developed to provide plant oil extraction.
For instance, U.S. Pat. No. 5,516,923 discloses a method of plant oil extraction, according to which grounded plant material is deposited into a reactor vessel, and vacuum is created in the reactor vessel. Liquid solvent is introduced into the reactor vessel and allowed to contact the plant material for a time sufficient to dissolve oil from the plant material, while the temperature in the reactor vessel is maintained at a level which prevents denaturing of constituent components of the plant oil and the plant material. Additional solvent vapors are introduced into the bottom of the reactor to cause mixing of the plant material and the solvent and separate fine particulate matter from heavier particles. Pressurized heated solvent vapors are introduced into the top of the reactor vessel while the liquid solvent and oil combination is being removed from the bottom of the reactor vessel through filters. To prevent clogging of filters in the bottom of the reactor vessel pressurized solvent vapors are forced through the filters into the bottom of the reactor vessel. The solvent and oil combination is transferred into a separator vessel, wherein the solvent is vaporized and removed for recycling, while the oil is removed into a holding tank.
U.S. Pat. No. 7,002,029 discloses a process for solvent extraction of oils, in an extraction chamber. According to this method, solvent mist with significant adiabatic cooling is introduced into the extraction chamber, whereby a pressure difference between the solvent inlet and outlet of the extraction chamber drives the solvent mist through the raw oil material. The solvent is fed to the extraction chamber at pressures exceeding atmospheric pressure, and the outlet of the extraction chamber is subject to a partial vacuum.
U.S. application Publication No. 2009/0028971 discloses a method utilizing compressed hydrocarbons. Residues from the crop and fruit treatment, especially from the treatment of pips and berries, are used as starting materials. The method is carried our without organic solvents, while applying low pressures and reduced extraction agent throughputs. Preferred extraction agents are ethane, propane, butane and the mixtures thereof, the extraction itself being carried out in batches at pressures of <50 mPa and temperatures of about 70° C., with an extraction agent throughput of between 4 and 20 kg/kg of starting materials.
U.S. application Publication No. 2011/0133120 teaches a method of plant oil extraction, which provides for a hermetically first tank coupled to a first valve, the first tank for storing a solvent comprising Butane, an extraction zone comprising an extraction chamber coupled between the first valve and a second valve, the extraction chamber having a filter proximate to the second valve; the extraction chamber has a volume between ¼ and ⅙ of the volume of the first tank. A filter separates flowing butane solvent and plant oil from organic plant material in the extraction chamber. A second tank has an exit valve for removing plant oil located on a bottom portion of the second tank, and an exit valve located near a top portion of the second tank.
U.S. application publication No. 2011/0100894 teaches a plant oil extraction device that has a main body member with a hollow interior that receives a plant. A filter member is removably mounted on the main body and has a groove therein that receives glass frit. Thus, when a solvent is placed in the hollow interior with the plant the glass frit filters the plant particulate allowing plant oil and solvent to flow into a receiving vessel. Once the oil is collected the filter member may be removed from the main body such that the glass frit can be cleaned of all plant particulate and be reused.
A commercially available example of an extraction distillation unit is a Tamisium Extractor manufacture by TamiE of Cleburne, Tex. This extractor utilizes several different single solvents, and sometimes co-solvents, a primary solvent and a carrier solvent; in total three distinct types of extractions.
While the methods discussed above may work satisfactory in different environments, there is a need for an easy-to-operate inexpensive apparatus and method of plant oil extraction that can be used in a non-industrial setting by a cosmetics laboratory, small shop and by a consumer without the need to mix solvents during an extraction process.